There is a trend towards increasingly large passenger aircraft, for which it is desirable to have correspondingly large wing spans. However, the maximum aircraft span is effectively limited by airport operating rules which govern various clearances required when manoeuvring around the airport (such as the span and/or ground clearance required for gate entry and safe taxiway usage).
To address this problem, various arrangements comprising moveable wing tip devices, that specifically enable the span to be reduced in a ground configuration, have been suggested. US2013/0099060, and WO2015/150816 are examples of moveable wing tip devices in which the wing tip device is moveable about a hinge. WO2015/150835 is an example of another moveable wing tip device. In the arrangement of WO2015/150835 the wing tip device and the fixed wing are separated along an oblique cut plane and the wing tip device is rotatable about an axis of rotation perpendicular to that cut plane.
Small gaps, steps or other mismatch at the interface between the outer end of the fixed wing and the inner end of the wing tip device, when the moveable wing tip device is in the flight configuration, can create aerodynamic penalties (e.g. drag and pressure leakage). In some moveable wing tip arrangements, it has been difficult to provide an interface that eliminates these features. For example, in some arrangements, controlling the tolerances in the vicinity of the interface has been found to be difficult.
Aspects of the present invention seek to address this problem, and may enable an improved interface between the fixed wing and the wing tip device.